Checked 
But from master page my Menu item get collapsed 
I did not use any HTMl tag 
 
Eg 
Home Manu Admin  ( before pront button ) 
After print button
my Menu item collapsed 
Home
Menu
Admin 
 
My print function is 
my code is 
 
   Gridview1.UseAccessibleHeader = True
            Gridview1.HeaderRow.TableSection = TableRowSection.TableHeader
            Gridview1.Attributes("style") = "border-collapse:separate"
            Dim isFirst As Boolean = False
            For Each row As GridViewRow In Gridview1.Rows
                If row.RowIndex Mod 18 = 0 AndAlso row.RowIndex <> 0 AndAlso isFirst = False Then
                    row.Attributes.Add("style", "page-break-after:always;")
                    isFirst = True
                End If
                If row.RowIndex Mod 23 = 0 AndAlso row.RowIndex <> 0 AndAlso isFirst = True Then
                    row.Attributes.Add("style", "page-break-after:always;")
                    isFirst = True
                End If
            Next
            Gridview1.AllowPaging = False
            Gridview1.DataBind()
            '  Gridview1.Width = "800"
            Dim sw As New StringWriter()
            Dim hw As New HtmlTextWriter(sw)
            grdpanel.RenderControl(hw)
            Dim gridHTML As String = sw.ToString().Replace("""", "'") _
                 .Replace(System.Environment.NewLine, "")
            Dim sb As New StringBuilder()
            sb.Append("<script type = 'text/javascript'>")
            sb.Append("window.onload = new function(){")
            sb.Append("var printWin = window.open('', '', 'left=0")
            sb.Append(",top=0,width=960,height=600,status=0');")
            sb.Append("printWin.document.write(""")
            Dim style As String = "<style type = 'text/css'>thead {display:table-header-group;} tfoot{display:table-footer-group;}</style>"
            sb.Append(style & gridHTML)
            sb.Append(""");")
            sb.Append("printWin.document.close();")
            sb.Append("printWin.focus();")
            sb.Append("printWin.print();")
            sb.Append("printWin.close();};")
            sb.Append("</script>")
            ClientScript.RegisterStartupScript(Me.[GetType](), "Gridview1List", sb.ToString())
            Gridview1.AllowPaging = True
            Gridview1.DataBind()
 
Can you please tell me why this is happening ?